What Does an Insulin Syringe Look Like?

Insulin is a hormone that allows the body to turn blood glucose into a form of energy the cells can use. Diabetics who produce little or no insulin must take the hormone via an injection, usually multiple times a day. Following is information on the parts of an insulin syringe and how it works.

Barrel

• The barrel of the syringe is the chamber that holds the insulin for injection. Unit measurements are marked on the side of the barrel to measure your dosage. Barrel sizes range from .25 mm, which holds up to 25 units of insulin, to1 ml, which holds up to 100 units. Choosing a syringe that is the correct size for your prescribed insulin dosage is important, according to the American Diabetes Association (ADA). "With a barrel that's too big you'll have trouble measuring out a small dosage," according to the ADA. "Though all syringes have markings on the barrel that indicate dosage, different brands may mark these lines differently. For example, on one syringe, each line may indicate a single unit; another syringe may indicate two units with each line; others may have smaller, half-unit markings for people (children in particular) who require extra-small doses."

Plunger

• The plunger, which fits tightly inside the barrel, consists of a slim plastic rod with a rubber tip on one end and a flat round disc on the other. Once the barrel is filled, you push the flat disc to give yourself an injection. As you depress the plunger, its rubber tip pushes the insulin out of the barrel, through the needle and into your body.

Needle

• The gauge of the needle is a measurement of its inner diameter. The higher the gauge number, the thinner the needle. Insulin needles range from 28 gauge to 31 gauge. Insulin should be injected subcutaneously (under the skin), so insulin needles are shorter than needles designed for other types of injections. Insulin needles are usually ½-inch long, but they can be as short as 5/16 inch. The length of the needle you choose is mostly a matter of preference, but children and very thin people may need the shortest needle, according to the ADA. "Apart from the perception of pain a needle causes, there is no difference in needle lengths in terms of comfort," according to the ADA. "However, some very thin people may need a shorter needle to avoid injecting into their muscles."

Significance

• Diabetes is a widespread disease. Nearly 24 million people in the United States have diabetes and the number continues to grow, according to the Centers for Disease Control. Nearly 2 billion insulin syringes are manufactured each year to treat these individuals, according to the National Institutes of Health.

Disposal

• After an injection, dispose of the syringe in a puncture-proof container. Puncture-proof containers, often called sharps containers, can be purchased through pharmacies and medical supply stores.